The file P14_25.xlsx contains the quarterly numbers of applications for home mortgage loans at a branch office of Northern Central Bank.

a. Create a time series chart of the data. Based on what you see, which of the exponential smoothing models do you think will provide the best forecasting model? Why?

b. Use simple exponential smoothing to forecast these data, using a smoothing constant of 0.1.

c. Repeat part b, but search for the smoothing constant that makes RMSE as small as possible. Does it make much of an improvement over the model in part b? Is it guaranteed to produce better forecasts for the future?